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1 | \section{\class{wxArray}}\label{wxarray} | |
2 | ||
3 | This section describes the so called {\it dynamic arrays}. This is a C | |
4 | array-like data structure i.e. the member access time is constant (and not | |
5 | linear according to the number of container elements as for linked lists). However, these | |
6 | arrays are dynamic in the sense that they will automatically allocate more | |
7 | memory if there is not enough of it for adding a new element. They also perform | |
8 | range checking on the index values but in debug mode only, so please be sure to | |
9 | compile your application in debug mode to use it (see \helpref{debugging overview}{debuggingoverview} for | |
10 | details). So, unlike the arrays in some other | |
11 | languages, attempt to access an element beyond the arrays bound doesn't | |
12 | automatically expand the array but provokes an assertion failure instead in | |
13 | debug build and does nothing (except possibly crashing your program) in the | |
14 | release build. | |
15 | ||
16 | The array classes were designed to be reasonably efficient, both in terms of | |
17 | run-time speed and memory consumption and the executable size. The speed of | |
18 | array item access is, of course, constant (independent of the number of elements) | |
19 | making them much more efficient than linked lists (\helpref{wxList}{wxlist}). | |
20 | Adding items to the arrays is also implemented in more or less constant time - | |
21 | but the price is preallocating the memory in advance. In the \helpref{memory management}{wxarraymemorymanagement} section | |
22 | you may find some useful hints about optimizing wxArray memory usage. As for executable size, all | |
23 | wxArray functions are inline, so they do not take {\it any space at all}. | |
24 | ||
25 | wxWindows has three different kinds of array. All of them derive from | |
26 | wxBaseArray class which works with untyped data and can not be used directly. | |
27 | The standard macros WX\_DEFINE\_ARRAY(), WX\_DEFINE\_SORTED\_ARRAY() and | |
28 | WX\_DEFINE\_OBJARRAY() are used to define a new class deriving from it. The | |
29 | classes declared will be called in this documentation wxArray, wxSortedArray and | |
30 | wxObjArray but you should keep in mind that no classes with such names actually | |
31 | exist, each time you use one of WX\_DEFINE\_XXXARRAY macro you define a class | |
32 | with a new name. In fact, these names are "template" names and each usage of one | |
33 | of the macros mentioned above creates a template specialization for the given | |
34 | element type. | |
35 | ||
36 | wxArray is suitable for storing integer types and pointers which it does not | |
37 | treat as objects in any way, i.e. the element pointed to by the pointer is not | |
38 | deleted when the element is removed from the array. It should be noted that | |
39 | all of wxArray's functions are inline, so it costs strictly nothing to define as | |
40 | many array types as you want (either in terms of the executable size or the | |
41 | speed) as long as at least one of them is defined and this is always the case | |
42 | because wxArrays are used by wxWindows internally. This class has one serious | |
43 | limitation: it can only be used for storing integral types (bool, char, short, | |
44 | int, long and their unsigned variants) or pointers (of any kind). An attempt | |
45 | to use with objects of sizeof() greater than sizeof(long) will provoke a | |
46 | runtime assertion failure, however declaring a wxArray of floats will not (on | |
47 | the machines where sizeof(float) <= sizeof(long)), yet it will {\bf not} work, | |
48 | please use wxObjArray for storing floats and doubles (NB: a more efficient | |
49 | wxArrayDouble class is scheduled for the next release of wxWindows). | |
50 | ||
51 | wxSortedArray is a wxArray variant which should be used when searching in the | |
52 | array is a frequently used operation. It requires you to define an additional | |
53 | function for comparing two elements of the array element type and always stores | |
54 | its items in the sorted order (according to this function). Thus, it is | |
55 | \helpref{Index()}{wxarrayindex} function execution time is $O(log(N))$ instead of | |
56 | $O(N)$ for the usual arrays but the \helpref{Add()}{wxarrayadd} method is | |
57 | slower: it is $O(log(N))$ instead of constant time (neglecting time spent in | |
58 | memory allocation routine). However, in a usual situation elements are added to | |
59 | an array much less often than searched inside it, so wxSortedArray may lead to | |
60 | huge performance improvements compared to wxArray. Finally, it should be | |
61 | noticed that, as wxArray, wxSortedArray can be only used for storing integral | |
62 | types or pointers. | |
63 | ||
64 | wxObjArray class treats its elements like "objects". It may delete them when | |
65 | they are removed from the array (invoking the correct destructor) and copies | |
66 | them using the objects copy constructor. In order to implement this behaviour | |
67 | the definition of the wxObjArray arrays is split in two parts: first, you should | |
68 | declare the new wxObjArray class using WX\_DECLARE\_OBJARRAY() macro and then | |
69 | you must include the file defining the implementation of template type: | |
70 | <wx/arrimpl.cpp> and define the array class with WX\_DEFINE\_OBJARRAY() macro | |
71 | from a point where the full (as opposed to `forward') declaration of the array | |
72 | elements class is in scope. As it probably sounds very complicated here is an | |
73 | example: | |
74 | ||
75 | \begin{verbatim} | |
76 | #include <wx/dynarray.h> | |
77 | ||
78 | // we must forward declare the array because it is used inside the class | |
79 | // declaration | |
80 | class MyDirectory; | |
81 | class MyFile; | |
82 | ||
83 | // this defines two new types: ArrayOfDirectories and ArrayOfFiles which can be | |
84 | // now used as shown below | |
85 | WX_DECLARE_OBJARRAY(MyDirectory, ArrayOfDirectories); | |
86 | WX_DECLARE_OBJARRAY(MyFile, ArrayOfFiles); | |
87 | ||
88 | class MyDirectory | |
89 | { | |
90 | ... | |
91 | ArrayOfDirectories m_subdirectories; // all subdirectories | |
92 | ArrayOfFiles m_files; // all files in this directory | |
93 | }; | |
94 | ||
95 | ... | |
96 | ||
97 | // now that we have MyDirectory declaration in scope we may finish the | |
98 | // definition of ArrayOfDirectories -- note that this expands into some C++ | |
99 | // code and so should only be compiled once (i.e., don't put this in the | |
100 | // header, but into a source file or you will get linking errors) | |
101 | #include <wx/arrimpl.cpp> // this is a magic incantation which must be done! | |
102 | WX_DEFINE_OBJARRAY(ArrayOfDirectories); | |
103 | ||
104 | // that's all! | |
105 | \end{verbatim} | |
106 | ||
107 | It is not as elegant as writing | |
108 | ||
109 | \begin{verbatim} | |
110 | typedef std::vector<MyDirectory> ArrayOfDirectories; | |
111 | \end{verbatim} | |
112 | ||
113 | but is not that complicated and allows the code to be compiled with any, however | |
114 | dumb, C++ compiler in the world. | |
115 | ||
116 | Things are much simpler for wxArray and wxSortedArray however: it is enough | |
117 | just to write | |
118 | ||
119 | \begin{verbatim} | |
120 | WX_DEFINE_ARRAY(MyDirectory *, ArrayOfDirectories); | |
121 | WX_DEFINE_SORTED_ARRAY(MyFile *, ArrayOfFiles); | |
122 | \end{verbatim} | |
123 | ||
124 | \wxheading{See also:} | |
125 | ||
126 | \helpref{Container classes overview}{wxcontaineroverview}, \helpref{wxList}{wxlist} | |
127 | ||
128 | \wxheading{Include files} | |
129 | ||
130 | <wx/dynarray.h> for wxArray and wxSortedArray and additionally <wx/arrimpl.cpp> | |
131 | for wxObjArray. | |
132 | ||
133 | \latexignore{\rtfignore{\wxheading{Function groups}}} | |
134 | ||
135 | \membersection{Macros for template array definition} | |
136 | ||
137 | To use an array you must first define the array class. This is done with the | |
138 | help of the macros in this section. The class of array elements must be (at | |
139 | least) forward declared for WX\_DEFINE\_ARRAY, WX\_DEFINE\_SORTED\_ARRAY and | |
140 | WX\_DECLARE\_OBJARRAY macros and must be fully declared before you use | |
141 | WX\_DEFINE\_OBJARRAY macro. | |
142 | ||
143 | \helpref{WX\_DEFINE\_ARRAY}{wxdefinearray}\\ | |
144 | \helpref{WX\_DEFINE\_EXPORTED\_ARRAY}{wxdefinearray}\\ | |
145 | \helpref{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{wxdefinearray}\\ | |
146 | \helpref{WX\_DEFINE\_SORTED\_ARRAY}{wxdefinesortedarray}\\ | |
147 | \helpref{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\ | |
148 | \helpref{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\ | |
149 | \helpref{WX\_DECLARE\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\ | |
150 | \helpref{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\ | |
151 | \helpref{WX\_DEFINE\_OBJARRAY}{wxdefineobjarray}\\ | |
152 | \helpref{WX\_DEFINE\_EXPORTED\_OBJARRAY}{wxdefineobjarray}\\ | |
153 | \helpref{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{wxdefineobjarray} | |
154 | ||
155 | \membersection{Constructors and destructors} | |
156 | ||
157 | Array classes are 100\% C++ objects and as such they have the appropriate copy | |
158 | constructors and assignment operators. Copying wxArray just copies the elements | |
159 | but copying wxObjArray copies the arrays items. However, for memory-efficiency | |
160 | sake, neither of these classes has virtual destructor. It is not very important | |
161 | for wxArray which has trivial destructor anyhow, but it does mean that you | |
162 | should avoid deleting wxObjArray through a wxBaseArray pointer (as you would | |
163 | never use wxBaseArray anyhow it shouldn't be a problem) and that you should not | |
164 | derive your own classes from the array classes. | |
165 | ||
166 | \helpref{wxArray default constructor}{wxarrayctordef}\\ | |
167 | \helpref{wxArray copy constructors and assignment operators}{wxarrayctorcopy}\\ | |
168 | \helpref{\destruct{wxArray}}{wxarraydtor} | |
169 | ||
170 | \membersection{Memory management}\label{wxarraymemorymanagement} | |
171 | ||
172 | Automatic array memory management is quite trivial: the array starts by | |
173 | preallocating some minimal amount of memory (defined by | |
174 | WX\_ARRAY\_DEFAULT\_INITIAL\_SIZE) and when further new items exhaust already | |
175 | allocated memory it reallocates it adding 50\% of the currently allocated | |
176 | amount, but no more than some maximal number which is defined by | |
177 | ARRAY\_MAXSIZE\_INCREMENT constant. Of course, this may lead to some memory | |
178 | being wasted (ARRAY\_MAXSIZE\_INCREMENT in the worst case, i.e. 4Kb in the | |
179 | current implementation), so the \helpref{Shrink()}{wxarrayshrink} function is | |
180 | provided to deallocate the extra memory. The \helpref{Alloc()}{wxarrayalloc} | |
181 | function can also be quite useful if you know in advance how many items you are | |
182 | going to put in the array and will prevent the array code from reallocating the | |
183 | memory more times than needed. | |
184 | ||
185 | \helpref{Alloc}{wxarrayalloc}\\ | |
186 | \helpref{Shrink}{wxarrayshrink} | |
187 | ||
188 | \membersection{Number of elements and simple item access} | |
189 | ||
190 | Functions in this section return the total number of array elements and allow to | |
191 | retrieve them - possibly using just the C array indexing $[]$ operator which | |
192 | does exactly the same as \helpref{Item()}{wxarrayitem} method. | |
193 | ||
194 | \helpref{Count}{wxarraycount}\\ | |
195 | \helpref{GetCount}{wxarraygetcount}\\ | |
196 | \helpref{IsEmpty}{wxarrayisempty}\\ | |
197 | \helpref{Item}{wxarrayitem}\\ | |
198 | \helpref{Last}{wxarraylast} | |
199 | ||
200 | \membersection{Adding items} | |
201 | ||
202 | \helpref{Add}{wxarrayadd}\\ | |
203 | \helpref{Insert}{wxarrayinsert}\\ | |
204 | \helpref{SetCount}{wxarraysetcount}\\ | |
205 | \helpref{WX\_APPEND\_ARRAY}{wxappendarray} | |
206 | ||
207 | \membersection{Removing items} | |
208 | ||
209 | \helpref{WX\_CLEAR\_ARRAY}{wxcleararray}\\ | |
210 | \helpref{Empty}{wxarrayempty}\\ | |
211 | \helpref{Clear}{wxarrayclear}\\ | |
212 | \helpref{RemoveAt}{wxarrayremoveat}\\ | |
213 | \helpref{Remove}{wxarrayremove} | |
214 | ||
215 | \membersection{Searching and sorting} | |
216 | ||
217 | \helpref{Index}{wxarrayindex}\\ | |
218 | \helpref{Sort}{wxarraysort} | |
219 | ||
220 | %%%%% MEMBERS HERE %%%%% | |
221 | \helponly{\insertatlevel{2}{ | |
222 | ||
223 | \wxheading{Members} | |
224 | ||
225 | }} | |
226 | ||
227 | \membersection{WX\_DEFINE\_ARRAY}\label{wxdefinearray} | |
228 | ||
229 | \func{}{WX\_DEFINE\_ARRAY}{\param{}{T}, \param{}{name}} | |
230 | ||
231 | \func{}{WX\_DEFINE\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}} | |
232 | ||
233 | \func{}{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}, \param{}{exportspec}} | |
234 | ||
235 | This macro defines a new array class named {\it name} and containing the | |
236 | elements of type {\it T}. The second form is used when compiling wxWindows as | |
237 | a DLL under Windows and array needs to be visible outside the DLL. The third is | |
238 | needed for exporting an array from a user DLL. | |
239 | ||
240 | Example: | |
241 | ||
242 | \begin{verbatim} | |
243 | WX_DEFINE_ARRAY(int, wxArrayInt); | |
244 | ||
245 | class MyClass; | |
246 | WX_DEFINE_ARRAY(MyClass *, wxArrayOfMyClass); | |
247 | \end{verbatim} | |
248 | ||
249 | Note that wxWindows predefines the following standard array classes: wxArrayInt, | |
250 | wxArrayLong and wxArrayPtrVoid. | |
251 | ||
252 | \membersection{WX\_DEFINE\_SORTED\_ARRAY}\label{wxdefinesortedarray} | |
253 | ||
254 | \func{}{WX\_DEFINE\_SORTED\_ARRAY}{\param{}{T}, \param{}{name}} | |
255 | ||
256 | \func{}{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}} | |
257 | ||
258 | \func{}{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}} | |
259 | ||
260 | This macro defines a new sorted array class named {\it name} and containing | |
261 | the elements of type {\it T}. The second form is used when compiling wxWindows as | |
262 | a DLL under Windows and array needs to be visible outside the DLL. The third is | |
263 | needed for exporting an array from a user DLL. | |
264 | ||
265 | Example: | |
266 | ||
267 | \begin{verbatim} | |
268 | WX_DEFINE_SORTED_ARRAY(int, wxSortedArrayInt); | |
269 | ||
270 | class MyClass; | |
271 | WX_DEFINE_SORTED_ARRAY(MyClass *, wxArrayOfMyClass); | |
272 | \end{verbatim} | |
273 | ||
274 | You will have to initialize the objects of this class by passing a comparison | |
275 | function to the array object constructor like this: | |
276 | ||
277 | \begin{verbatim} | |
278 | int CompareInts(int n1, int n2) | |
279 | { | |
280 | return n1 - n2; | |
281 | } | |
282 | ||
283 | wxSortedArrayInt sorted(CompareInts); | |
284 | ||
285 | int CompareMyClassObjects(MyClass *item1, MyClass *item2) | |
286 | { | |
287 | // sort the items by their address... | |
288 | return Stricmp(item1->GetAddress(), item2->GetAddress()); | |
289 | } | |
290 | ||
291 | wxArrayOfMyClass another(CompareMyClassObjects); | |
292 | \end{verbatim} | |
293 | ||
294 | \membersection{WX\_DECLARE\_OBJARRAY}\label{wxdeclareobjarray} | |
295 | ||
296 | \func{}{WX\_DECLARE\_OBJARRAY}{\param{}{T}, \param{}{name}} | |
297 | ||
298 | \func{}{WX\_DECLARE\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}} | |
299 | ||
300 | \func{}{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}} | |
301 | ||
302 | This macro declares a new object array class named {\it name} and containing | |
303 | the elements of type {\it T}. The second form is used when compiling wxWindows as | |
304 | a DLL under Windows and array needs to be visible outside the DLL. The third is | |
305 | needed for exporting an array from a user DLL. | |
306 | ||
307 | Example: | |
308 | ||
309 | \begin{verbatim} | |
310 | class MyClass; | |
311 | WX_DECLARE_OBJARRAY(MyClass, wxArrayOfMyClass); // note: not "MyClass *"! | |
312 | \end{verbatim} | |
313 | ||
314 | You must use \helpref{WX\_DEFINE\_OBJARRAY()}{wxdefineobjarray} macro to define | |
315 | the array class - otherwise you would get link errors. | |
316 | ||
317 | \membersection{WX\_DEFINE\_OBJARRAY}\label{wxdefineobjarray} | |
318 | ||
319 | \func{}{WX\_DEFINE\_OBJARRAY}{\param{}{name}} | |
320 | ||
321 | \func{}{WX\_DEFINE\_EXPORTED\_OBJARRAY}{\param{}{name}} | |
322 | ||
323 | \func{}{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{\param{}{name}} | |
324 | ||
325 | This macro defines the methods of the array class {\it name} not defined by the | |
326 | \helpref{WX\_DECLARE\_OBJARRAY()}{wxdeclareobjarray} macro. You must include the | |
327 | file <wx/arrimpl.cpp> before using this macro and you must have the full | |
328 | declaration of the class of array elements in scope! If you forget to do the | |
329 | first, the error will be caught by the compiler, but, unfortunately, many | |
330 | compilers will not give any warnings if you forget to do the second - but the | |
331 | objects of the class will not be copied correctly and their real destructor will | |
332 | not be called. The latter two forms are merely aliases of the first to satisfy | |
333 | some people's sense of symmetry when using the exported declarations. | |
334 | ||
335 | Example of usage: | |
336 | ||
337 | \begin{verbatim} | |
338 | // first declare the class! | |
339 | class MyClass | |
340 | { | |
341 | public: | |
342 | MyClass(const MyClass&); | |
343 | ||
344 | ... | |
345 | ||
346 | virtual ~MyClass(); | |
347 | }; | |
348 | ||
349 | #include <wx/arrimpl.cpp> | |
350 | WX_DEFINE_OBJARRAY(wxArrayOfMyClass); | |
351 | \end{verbatim} | |
352 | ||
353 | \membersection{WX\_APPEND\_ARRAY}\label{wxappendarray} | |
354 | ||
355 | \func{void}{WX\_APPEND\_ARRAY}{\param{wxArray\& }{array}, \param{wxArray\& }{other}} | |
356 | ||
357 | This macro may be used to append all elements of the {\it other} array to the | |
358 | {\it array}. The two arrays must be of the same type. | |
359 | ||
360 | \membersection{WX\_CLEAR\_ARRAY}\label{wxcleararray} | |
361 | ||
362 | \func{void}{WX\_CLEAR\_ARRAY}{\param{wxArray\& }{array}} | |
363 | ||
364 | This macro may be used to delete all elements of the array before emptying it. | |
365 | It can not be used with wxObjArrays - but they will delete their elements anyhow | |
366 | when you call Empty(). | |
367 | ||
368 | \membersection{Default constructors}\label{wxarrayctordef} | |
369 | ||
370 | \func{}{wxArray}{\void} | |
371 | ||
372 | \func{}{wxObjArray}{\void} | |
373 | ||
374 | Default constructor initializes an empty array object. | |
375 | ||
376 | \func{}{wxSortedArray}{\param{int (*)(T first, T second)}{compareFunction}} | |
377 | ||
378 | There is no default constructor for wxSortedArray classes - you must initialize it | |
379 | with a function to use for item comparison. It is a function which is passed | |
380 | two arguments of type {\it T} where {\it T} is the array element type and which | |
381 | should return a negative, zero or positive value according to whether the first | |
382 | element passed to it is less than, equal to or greater than the second one. | |
383 | ||
384 | \membersection{wxArray copy constructor and assignment operator}\label{wxarrayctorcopy} | |
385 | ||
386 | \func{}{wxArray}{\param{const wxArray\& }{array}} | |
387 | ||
388 | \func{}{wxSortedArray}{\param{const wxSortedArray\& }{array}} | |
389 | ||
390 | \func{}{wxObjArray}{\param{const wxObjArray\& }{array}} | |
391 | ||
392 | \func{wxArray\&}{operator$=$}{\param{const wxArray\& }{array}} | |
393 | ||
394 | \func{wxSortedArray\&}{operator$=$}{\param{const wxSortedArray\& }{array}} | |
395 | ||
396 | \func{wxObjArray\&}{operator$=$}{\param{const wxObjArray\& }{array}} | |
397 | ||
398 | The copy constructors and assignment operators perform a shallow array copy | |
399 | (i.e. they don't copy the objects pointed to even if the source array contains | |
400 | the items of pointer type) for wxArray and wxSortedArray and a deep copy (i.e. | |
401 | the array element are copied too) for wxObjArray. | |
402 | ||
403 | \membersection{wxArray::\destruct{wxArray}}\label{wxarraydtor} | |
404 | ||
405 | \func{}{\destruct{wxArray}}{\void} | |
406 | ||
407 | \func{}{\destruct{wxSortedArray}}{\void} | |
408 | ||
409 | \func{}{\destruct{wxObjArray}}{\void} | |
410 | ||
411 | The wxObjArray destructor deletes all the items owned by the array. This is not | |
412 | done by wxArray and wxSortedArray versions - you may use | |
413 | \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro for this. | |
414 | ||
415 | \membersection{wxArray::Add}\label{wxarrayadd} | |
416 | ||
417 | \func{void}{Add}{\param{T }{item}, \param{size\_t}{ copies = $1$}} | |
418 | ||
419 | \func{void}{Add}{\param{T *}{item}} | |
420 | ||
421 | \func{void}{Add}{\param{T \&}{item}, \param{size\_t}{ copies = $1$}} | |
422 | ||
423 | Appends the given number of {\it copies} of the {\it item} to the array | |
424 | consisting of the elements of type {\it T}. | |
425 | ||
426 | The first version is used with wxArray and wxSortedArray. The second and the | |
427 | third are used with wxObjArray. There is an important difference between | |
428 | them: if you give a pointer to the array, it will take ownership of it, i.e. | |
429 | will delete it when the item is deleted from the array. If you give a reference | |
430 | to the array, however, the array will make a copy of the item and will not take | |
431 | ownership of the original item. Once again, it only makes sense for wxObjArrays | |
432 | because the other array types never take ownership of their elements. Also note | |
433 | that you cannot append more than one pointer as reusing it would lead to | |
434 | deleting it twice (or more) and hence to a crash. | |
435 | ||
436 | You may also use \helpref{WX\_APPEND\_ARRAY}{wxappendarray} macro to append all | |
437 | elements of one array to another one but it is more efficient to use | |
438 | {\it copies} parameter and modify the elements in place later if you plan to | |
439 | append a lot of items. | |
440 | ||
441 | \membersection{wxArray::Alloc}\label{wxarrayalloc} | |
442 | ||
443 | \func{void}{Alloc}{\param{size\_t }{count}} | |
444 | ||
445 | Preallocates memory for a given number of array elements. It is worth calling | |
446 | when the number of items which are going to be added to the array is known in | |
447 | advance because it will save unneeded memory reallocation. If the array already | |
448 | has enough memory for the given number of items, nothing happens. | |
449 | ||
450 | \membersection{wxArray::Clear}\label{wxarrayclear} | |
451 | ||
452 | \func{void}{Clear}{\void} | |
453 | ||
454 | This function does the same as \helpref{Empty()}{wxarrayempty} and additionally | |
455 | frees the memory allocated to the array. | |
456 | ||
457 | \membersection{wxArray::Count}\label{wxarraycount} | |
458 | ||
459 | \constfunc{size\_t}{Count}{\void} | |
460 | ||
461 | Same as \helpref{GetCount()}{wxarraygetcount}. This function is deprecated - | |
462 | it exists only for compatibility. | |
463 | ||
464 | \membersection{wxObjArray::Detach}\label{wxobjarraydetach} | |
465 | ||
466 | \func{T *}{Detach}{\param{size\_t }{index}} | |
467 | ||
468 | Removes the element from the array, but, unlike, | |
469 | \helpref{Remove()}{wxarrayremove} doesn't delete it. The function returns the | |
470 | pointer to the removed element. | |
471 | ||
472 | \membersection{wxArray::Empty}\label{wxarrayempty} | |
473 | ||
474 | \func{void}{Empty}{\void} | |
475 | ||
476 | Empties the array. For wxObjArray classes, this destroys all of the array | |
477 | elements. For wxArray and wxSortedArray this does nothing except marking the | |
478 | array of being empty - this function does not free the allocated memory, use | |
479 | \helpref{Clear()}{wxarrayclear} for this. | |
480 | ||
481 | \membersection{wxArray::GetCount}\label{wxarraygetcount} | |
482 | ||
483 | \constfunc{size\_t}{GetCount}{\void} | |
484 | ||
485 | Return the number of items in the array. | |
486 | ||
487 | \membersection{wxArray::Index}\label{wxarrayindex} | |
488 | ||
489 | \func{int}{Index}{\param{T\& }{item}, \param{bool }{searchFromEnd = false}} | |
490 | ||
491 | \func{int}{Index}{\param{T\& }{item}} | |
492 | ||
493 | The first version of the function is for wxArray and wxObjArray, the second is | |
494 | for wxSortedArray only. | |
495 | ||
496 | Searches the element in the array, starting from either beginning or the end | |
497 | depending on the value of {\it searchFromEnd} parameter. wxNOT\_FOUND is | |
498 | returned if the element is not found, otherwise the index of the element is | |
499 | returned. | |
500 | ||
501 | Linear search is used for the wxArray and wxObjArray classes but binary search | |
502 | in the sorted array is used for wxSortedArray (this is why searchFromEnd | |
503 | parameter doesn't make sense for it). | |
504 | ||
505 | {\bf NB:} even for wxObjArray classes, the operator==() of the elements in the | |
506 | array is {\bf not} used by this function. It searches exactly the given | |
507 | element in the array and so will only succeed if this element had been | |
508 | previously added to the array, but fail even if another, identical, element is | |
509 | in the array. | |
510 | ||
511 | \membersection{wxArray::Insert}\label{wxarrayinsert} | |
512 | ||
513 | \func{void}{Insert}{\param{T }{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}} | |
514 | ||
515 | \func{void}{Insert}{\param{T *}{item}, \param{size\_t }{n}} | |
516 | ||
517 | \func{void}{Insert}{\param{T \&}{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}} | |
518 | ||
519 | Insert the given number of {\it copies} of the {\it item} into the array before | |
520 | the existing item {\it n} - thus, {\it Insert(something, 0u)} will insert an | |
521 | item in such way that it will become the first array element. | |
522 | ||
523 | Please see \helpref{Add()}{wxarrayadd} for explanation of the differences | |
524 | between the overloaded versions of this function. | |
525 | ||
526 | \membersection{wxArray::IsEmpty}\label{wxarrayisempty} | |
527 | ||
528 | \constfunc{bool}{IsEmpty}{\void} | |
529 | ||
530 | Returns true if the array is empty, false otherwise. | |
531 | ||
532 | \membersection{wxArray::Item}\label{wxarrayitem} | |
533 | ||
534 | \constfunc{T\&}{Item}{\param{size\_t }{index}} | |
535 | ||
536 | Returns the item at the given position in the array. If {\it index} is out of | |
537 | bounds, an assert failure is raised in the debug builds but nothing special is | |
538 | done in the release build. | |
539 | ||
540 | The returned value is of type "reference to the array element type" for all of | |
541 | the array classes. | |
542 | ||
543 | \membersection{wxArray::Last}\label{wxarraylast} | |
544 | ||
545 | \constfunc{T\&}{Last}{\void} | |
546 | ||
547 | Returns the last element in the array, i.e. is the same as Item(GetCount() - 1). | |
548 | An assert failure is raised in the debug mode if the array is empty. | |
549 | ||
550 | The returned value is of type "reference to the array element type" for all of | |
551 | the array classes. | |
552 | ||
553 | \membersection{wxArray::Remove}\label{wxarrayremove} | |
554 | ||
555 | \func{\void}{Remove}{\param{T }{item}} | |
556 | ||
557 | Removes an element from the array by value: the first item of the | |
558 | array equal to {\it item} is removed, an assert failure will result from an | |
559 | attempt to remove an item which doesn't exist in the array. | |
560 | ||
561 | When an element is removed from wxObjArray it is deleted by the array - use | |
562 | \helpref{Detach()}{wxobjarraydetach} if you don't want this to happen. On the | |
563 | other hand, when an object is removed from a wxArray nothing happens - you | |
564 | should delete it manually if required: | |
565 | ||
566 | \begin{verbatim} | |
567 | T *item = array[n]; | |
568 | delete item; | |
569 | array.Remove(n) | |
570 | \end{verbatim} | |
571 | ||
572 | See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all | |
573 | elements of a wxArray (supposed to contain pointers). | |
574 | ||
575 | \membersection{wxArray::RemoveAt}\label{wxarrayremoveat} | |
576 | ||
577 | \func{\void}{RemoveAt}{\param{size\_t }{index}, \param{size\_t }{count = $1$}} | |
578 | ||
579 | Removes {\it count} elements starting at {\it index} from the array. When an | |
580 | element is removed from wxObjArray it is deleted by the array - use | |
581 | \helpref{Detach()}{wxobjarraydetach} if you don't want this to happen. On | |
582 | the other hand, when an object is removed from a wxArray nothing happens - | |
583 | you should delete it manually if required: | |
584 | ||
585 | \begin{verbatim} | |
586 | T *item = array[n]; | |
587 | delete item; | |
588 | array.RemoveAt(n) | |
589 | \end{verbatim} | |
590 | ||
591 | See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all | |
592 | elements of a wxArray (supposed to contain pointers). | |
593 | ||
594 | \membersection{wxArray::SetCount}\label{wxarraysetcount} | |
595 | ||
596 | \func{void}{SetCount}{\param{size\_t }{count}, \param{T }{defval = T($0$)}} | |
597 | ||
598 | This function ensures that the number of array elements is at least | |
599 | {\it count}. If the array has already {\it count} or mroe items, nothing is | |
600 | done. Otherwise, {\tt count - GetCount()} elements are added and initialized to | |
601 | the value {\it defval}. | |
602 | ||
603 | \wxheading{See also} | |
604 | ||
605 | \helpref{GetCount}{wxarraygetcount} | |
606 | ||
607 | \membersection{wxArray::Shrink}\label{wxarrayshrink} | |
608 | ||
609 | \func{void}{Shrink}{\void} | |
610 | ||
611 | Frees all memory unused by the array. If the program knows that no new items | |
612 | will be added to the array it may call Shrink() to reduce its memory usage. | |
613 | However, if a new item is added to the array, some extra memory will be | |
614 | allocated again. | |
615 | ||
616 | \membersection{wxArray::Sort}\label{wxarraysort} | |
617 | ||
618 | \func{void}{Sort}{\param{CMPFUNC<T> }{compareFunction}} | |
619 | ||
620 | The notation CMPFUNC<T> should be read as if we had the following declaration: | |
621 | ||
622 | \begin{verbatim} | |
623 | template int CMPFUNC(T *first, T *second); | |
624 | \end{verbatim} | |
625 | ||
626 | where {\it T} is the type of the array elements. I.e. it is a function returning | |
627 | {\it int} which is passed two arguments of type {\it T *}. | |
628 | ||
629 | Sorts the array using the specified compare function: this function should | |
630 | return a negative, zero or positive value according to whether the first element | |
631 | passed to it is less than, equal to or greater than the second one. | |
632 | ||
633 | wxSortedArray doesn't have this function because it is always sorted. | |
634 |